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United States Patent |
5,543,547
|
Iwane
,   et al.
|
August 6, 1996
|
Method of producing aromatic carbonate
Abstract
The present invention relates to a method of producing an aromatic
carbonate by reacting an aromatic hydroxy compound, carbon monoxide and
oxygen using as a catalyst a specified catalyst system containing
palladium and cerium compounds. Specifically, the present invention
relates to a method of producing an aromatic carbonate by reacting an
aromatic hydroxy compound, carbon monoxide and oxygen in the presence of a
catalyst containing the following compounds:
(A) at least one selected from palladium and palladium compounds;
(B) at least one of trivalent or tetravalent cerium compounds;
(C) at least one selected from quaternary ammonium salts and quaternary
phosphonium salts;
(D) at least one selected from quinones and reduction products thereof,
i.e., aromatic diols; or
(A) and (B) components of the above; and
(E) at least one inorganic halide selected from alkali metal halides and
alkali earth metal halides.
Inventors:
|
Iwane; Hiroshi (Inashiki-gun, JP);
Miyagi; Hidekazu (Inashiki-gun, JP);
Imada; Satoshi (Inashiki-gun, JP);
Seo; Shoichi (Inashiki-gun, JP);
Yoneyama; Takahiro (Inashiki-gun, JP)
|
Assignee:
|
Mitsubishi Chemical Corporation (Tokyo, JP)
|
Appl. No.:
|
384258 |
Filed:
|
February 3, 1995 |
Foreign Application Priority Data
| Mar 08, 1993[JP] | 5-046740 |
| Jun 28, 1993[JP] | 5-157216 |
Current U.S. Class: |
558/274; 558/270 |
Intern'l Class: |
C07C 069/96 |
Field of Search: |
558/274,270
|
References Cited
U.S. Patent Documents
4201721 | May., 1980 | Hallgren | 558/270.
|
5132447 | Jul., 1992 | King, Jr. | 558/270.
|
5142086 | Aug., 1992 | King, Jr. et al. | 558/274.
|
Primary Examiner: Killos; Paul J.
Assistant Examiner: Jones; Dwayne C.
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier & Neustadt; P.C.
Parent Case Text
This application is a continuation of application Ser. No. 08/160,145,
filed on Dec. 2, 1993, now abandoned.
Claims
What is claimed is:
1. A method of producing an aromatic carbonate by reacting an aromatic
hydroxy compound, carbon monoxide and oxygen, wherein reaction is effected
under pressure within the range of 0.1 to 500 Kg/cm.sup.2 at a temperature
of 20.degree. to 300.degree. C., in a reaction system in the presence of
the following compounds:
(A) at least one member selected from the group consisting of palladium and
palladium compounds;
(B) at least one trivalent or tetravalent cerium compound;
(C) at least one member selected from the group consisting of quaternary
ammonium salts and quaternary phosphonium salts; and
(D) at least one member selected from the group consisting of quinones and
reduction products thereof, the molar ratio of component (A) to the
aromatic hydroxy compound being within the range of 10.sup.-5 :1 to 1:1
and a molar ratio of the component (B) to the component (A) being within
the range 10.sup.-2 :1 to 10.sup.2 :1.
2. A method according to claim 1, wherein the molar ratio of the component
(A) to the aromatic hydroxy compound is within the range of 10.sup.-4 :1
to 10.sup.-1 :1.
3. A method according to claim 1, wherein the molar ratio of the component
(B) to the component (A) is within the range of 10.sup.-1 :1 to 10:1.
4. A method according to claim 1, wherein the reaction pressure is within
the range of 1 to 250 Kg/cm.sup.2.
5. A method according to claim 1, wherein the reaction temperature is
within the range of 60.degree. to 250.degree. C.
6. A method according to claim 1, wherein said quaternary ammonium salts
are quaternary ammonium halides and said quaternary phosphonium salts are
quaternary phosphonium halides.
7. A method according to claim 1, wherein the molar ratio of the component
(C) to the component (A) is within the range of 10.sup.-1 :1 to 10.sup.2
:1, and the molar ratio of the component (D) to the component (A) is
within the range of 10.sup.-1 :1 to 10.sup.3 :1.
8. A method according to claim 7, wherein the molar ratio of the component
(C) to the component (A) is from 10.sup.-1 :1 to 50:1, and the molar ratio
of the component (D) to the component (A) is from 10.sup.-1 :1 to 40:1.
9. A method of producing an aromatic carbonate by reacting an aromatic
hydroxy compound, carbon monoxide and oxygen, wherein reaction is effected
under pressure within the range of 0.1 to 500 Kg/cm.sup.2 at temperature
of 20.degree. to 300.degree. C., in a reaction system in the presence of
the following compounds:
(A) at least one member selected from the group consisting of palladium and
palladium compounds;
(B) at least one trivalent or tetravalent cerium compound; and
(E) at least one inorganic halide selected from the group consisting of
alkali metal chlorides and bromides and alkali earth metal chlorides and
bromides, the molar ratio of component (A) to the aromatic hydroxy
compound being within the range of 10.sup.-5 :1 to 1:1 and a molar ratio
of the component (B) to the component (A) being within the range of
10.sup.-2 :1 to 10.sup.2 :1.
10. A method according to claim 9, wherein the molar ratio of the component
(A) to the aromatic hydroxy compound is within the range of 10.sup.-4 :1
to 10.sup.- :1.
11. A method according to claim 9, wherein the molar ratio of the component
(B) to the component (A) is within the range of 10.sup.-1 :1 to 10:1.
12. A method according to claim 9, wherein the molar ratio of the component
(E) to the component (A) is within the range of 10.sup.-2 :1 to 10.sup.3
:1.
13. A method according to claim 9, wherein the inorganic halide is select-d
from the group consisting of cesium chloride, sodium bromide, potassium
bromide, rubidium bromide, cesium bromide an barium bromide.
14. A method according to claim 9, wherein the reaction pressure is within
the range of 1 to 250 Kg/cm.sup.2.
15. A method according to claim 9, wherein the reaction temperature is
within the range of 60.degree. to 250.degree. C.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of producing an aromatic
carbonate from an aromatic hydroxy compound, carbon monoxide and oxygen
using a specified catalyst system. An aromatic carbonate, particularly
diphenyl carbonate is useful as a raw material for polycarbonate or the
like.
2. Description of the Related Art
A method of reacting an aromatic hydroxy compound with phosgene is
generally used for producing an aromatic carbonate. However, this method
has many problems as an industrial production method because of the high
toxicity of phosgene and the by-production of large amounts of inorganic
salts.
Some methods have thus been proposed which do not use phosgene in which an
aromatic carbonate is produced from an aromatic hydroxy compound, carbon
monoxide and oxygen.
Japanese Patent Publication No. 56-38144 discloses a method which uses as a
catalyst a palladium compound, a compound containing a metal from the
groups IIIA, IVA, VA, VIA, IB, IIB, VIB or VIIB in the periodic table, and
a base. Japanese Patent Publication No. 56-38145 discloses a method which
uses a palladium compound, a manganese or cobalt complex, a base and a
desiccating agent. Japanese Patent Laid-Open No. 1-165551 discloses a
method which uses a palladium compound, iodine and zeolite. Japanese
Patent Laid-Open No. 2-104564 discloses a method which uses a palladium
compound, a bivalent or trivalent manganese compound, tetraalkylammonium
halide and quinone. Japanese Patent Laid-Open No. 2-142754 discloses a
palladium compound, a bivalent or trivalent cobalt compound,
tetraalkylammonium halide and quinone. Japanese Patent Laid-Open No.
5-25095 discloses a method which uses a palladium compound, a cobalt
compound, an organic or inorganic halide and a basic compound.
Japanese Patent Laid-Open No. 5-58961 discloses a method which uses a
palladium compound, a cobalt compound and an alkali metal halide.
Japanese Patent Laid-Open No. 5-97775 (U.S. Pat. No. 5,142,086 and European
Patent Laid-Open No. 507,546-A2) discloses a method which uses a catalyst
system comprising (a) a palladium compound; (b) a quaternary ammonium
salt; (c) an inorganic compound as a cocatalyst selected from cobalt,
iron, cerium, manganese, molybdenum, samarium, vanadium chromium and
copper compounds; (d) an organic cocatalyst selected from aromatic
ketones, aliphatic ketones, and aromatic polycyclic coal tar hydrocarbons.
However, thee methods have critical problems concerning the low activity of
the catalyst used, and the low yield of an aromatic carbonate based on the
starting aromatic hydroxy compound, and re thus unsatisfactory as
industrial production methods. Tis is supposedly due to the phenomena
where the activity of the catalyst used is decreased by the water produced
by reaction, and that hydrolysis o an aromatic carbonate is accelerated in
the conventional catalyst system. The methods proposed for preventing this
phenomena include a method of using a large amount of coexisting
dehydrating agent or removing the water produced (Japanese Patent
Laid-Open No. 54-135744) and a method of distilling off the produced water
by reaction distillation (Japanese Patent Laid-Open No. 4-261142).
However, it could not be said that these methods have sufficient effects.
The conventional methods also have the problem that large amounts of
by-products, particularly phenoxyphenols which cannot be easily separated
from an intended product, are produced by oxidation of an aromatic hydroxy
compound.
SUMMARY OF THE INVENTION
It is an object of the present invention to solve the various problems of
conventional methods of producing aromatic carbonates from aromatic
hydroxy compounds, carbon monoxide and oxygen, and provide a method of
producing an intended aromatic carbonate with high yield and high
selectivity.
The inventors found that the yield of an aromatic carbonate can be improved
by using as a catalyst the specific catalyst system below containing
palladium and cerium compounds. The present invention provides an
industrial method of producing an aromatic carbonate which permits the
production of an aromatic carbonate with high yield while maintaining high
catalytic activity without using a large amount of dehydrating agent or
installing a specific apparatus.
The present invention provides a method of producing an aromatic carbonate
by reacting an aromatic hydroxy compound, carbon monoxide and oxygen,
wherein the reaction is effected in the presence of a catalyst consisting
of the following compounds:
(A) at least one selected from palladium and palladium compounds;
(B) at least one of trivalent or tetravalent cerium compounds;
(C) at least one selected from quaternary ammonium salts and quaternary
phosphonium salts; and
(D) at least one selected from quinones and reduction products thereof,
i.e., aromatic diols; or
(A) at least one selected from palladium and palladium compounds;
(B) at least one of trivalent or tetravalent cerium compounds; and
(E) at least one inorganic halide selected from alkali metal halides and
alkali earth metal halides.
DETAILED DESCRIPTION OF THE INVENTION
1. Raw Material
(1) Aromatic hydroxy compound
The aromatic hydroxy compound used in the present invention is an aromatic
mono- or poly-hydroxy compound. Examples of such hydroxy compounds include
phenol: substituted phenols such as p-cresol, 2,6-xylenol,
2,4,6-trimethylphenol, 2,3,4,5-tetramethylphenol, ethylphenol,
propylphenol, methoxyphenol, ethoxyphenol, chlorophenol,
2,4-dichlorophenol, bromophenol, 2,4-dibromophenol and position isomers
thereof; naphthol; substituted naphthols such as 2-methylnaphthol,
2-ethylnaphthol, 2-chloronaphthol, 2-bromonaphthol and position isomers
thereof; bisphenols such as 2,2-bis(4-hydroxyphenyl)propane and position
isomers thereof; various biphenols such as 4,4-biphenol and position
isomers thereof; various heteroaromatic hydroxy compounds such as
4-hydroxypyridine and position isomers thereof; and alkyl or halogen
substitution products of the above compounds. Of these compounds, phenol
is preferred.
(2) Carbon monoxide
The carbon monoxide used in the present invention may be high-purity carbon
monoxide or carbon monoxide diluted with another gas such as nitrogen,
argon, carbon dioxide or hydrogen, which have no bad effects on the
reaction.
(3) Oxygen
The oxygen used in the present invention may be high-purity oxygen, air or
oxygen diluted with another gas such as nitrogen, argon, carbon dioxide or
hydrogen, which have no bad effects on the reaction.
2. Catalyst
(A) Palladium or palladium compound
Examples of palladium or palladium compounds that can be used in the
present invention include palladium black; palladium/carbon,
palladium/alumina, palladium/silica and the like in which palladium is
supported on porous carriers; inorganic palladium salts such as palladium
chloride, palladium bromide, palladium iodide, palladium sulfate,
palladium nitrate and the like; organic palladium salts such as palladium
acetate, palladium oxalate. Further, palladium (II) acetylacetonate, a
palladium complex compound such as PdCl.sub.2 (PhCN).sub.2, PdCl.sub.2
(PPh.sub.3).sub.2, Pd(CO) (PPh.sub.3).sub.3, [Pd(NH.sub.3).sub.4
]Cl.sub.2, Pd(C.sub.2 H.sub.4) (PPh.sub.3).sub.2 or the like in which
carbon monoxide, nitrile, amine, phosphine or olefin is co-ordinated
around palladium, or a mixture of palladium and a compound which produces
the above complex compound in the reaction system can also be used.
Although a large amount of palladium component may be used in the reaction
without any problems, the molar ratio of the palladium component to the
aromatic hydroxy compound is preferably within the range of 10.sup.-5 to
1, more preferably 10.sup.-4 to 10.sup.-1.
(B) Trivalent or tetravalent cerium compound
Examples of trivalent or tetravalent cerium compounds that can be used in
the present invention include cerium/carbon, cerium/alumina, cerium/silica
and the like in which cerium is supported on porous carriers; inorganic
salts such as cerium chloride, cerium bromide, cerium sulfate, cerium
nitrate and the like; organic salts such as cerium acetate, cerium oxalate
and the like. Also cerium acetylacetonate, a cerium complex compound in
which carbon monoxide, a nitrile, an amine, a phosphine or an olefin is
co-ordinated around cerium, or a mixture of cerium and a compound which
produces the above complex compound in the reaction system may be used.
When cerium is supported on a porous carrier, cerium and palladium may, of
course, be supported on the same porous carrier.
Although the cerium component can be used in any desired ratio to the
palladium component, the molar ratio of the cerium component to the
palladium component is preferably within the range of 10.sup.-2 to
10.sup.2, more preferably 10.sup.-1 to 10.
(C) Quaternary ammonium salt or quaternary phosphonium salt (quaternary
onium salt)
The quaternary onium salt used in the present invention is a compound
expressed by the formula, R.sup.1 R.sup.2 R.sup.3 R.sup.4 NX or R.sup.1
R.sup.2 R.sup.3 R.sup.4 PX, wherein R.sup.1 through R.sup.4 are each an
alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 12
carbon atoms, and the groups R.sup.1 through R.sup.4 may be either the
same or different. Examples of the groups R.sup.1 through R.sup.4 through
R.sup.4 include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl,
cyclohexyl, phenyl tolyl, xylyl and naphthyl groups. X is an anion such as
a hydroxy group, a halogen anion such as a chloride anion, a bromide
anion, an iodide anion or the like; an organic anion such as a phenoxide
anion, an acetate anion or the like. Of these anions, a bromide anion is
preferred. A chloride anion has low activity, and an iodide anion causes
much combustion of carbon monoxide
Preferred examples of bromides include tetra-n-ethylammonium bromide,
tetra-n-butylammonium bromide and tetraphenylphosphonium bomide.
The molar ratio of the quaternary onium salt to the palladium component (A)
used in reaction is preferably within the range of 10.sup.-1 to 10.sup.3,
more preferably 1 to 10.sup.2, and most preferably 50 or less. Although
the molar ratio of the quaternary onium salt to the aromatic hydroxy
compound is not limited, the molar ratio is preferably within the range of
10.sup.-4 to 10.sup.-1, more preferably 10.sup.-3 to 10.sup.-2.
(D) Quinones and reduction products thereof, i.e., aromatic diols
Examples of quinones or reduction products thereof, i.e., aromatic diols,
that can be used in the present invention include 1,4-benzoquinone,
1,2-benzoquinone, catechol, naphthoquinone, anthraquinone, hydroquinone
and the like. Of these compounds, 1,4-benzoquinone and hydroquinone are
preferred.
The amount of the quinone or reduction product thereof used in the present
invention is not limited. However, if the amount is excessively small, the
yield and selectivity are decreased due to an increase in amount of the
oxidation by-products, and if the amount is excessively large, the
reaction is inhibited by the quinone or aromatic diol.
The molar ratio of the compound to the palladium component (A) is
preferably within the range of 10.sup.-1 to 10.sup.3, more preferably 1 to
10.sup.2, and most preferably 40 or less. The molar ratio of the compound
to the aromatic hydroxy compound is preferably within the range of
10.sup.-4 to 10.sup.-1, more preferably 10.sup.-3 to 10.sup.-2.
(E) Inorganic halide
The inorganic halide used in the present invention is an alkali metal or
alkali earth metal halide. A chloride and a bromide are preferred as such
halides. Specifically, cesium chloride, sodium bromide, potassium bromide,
rubidium bromide, cesium bromide, and barium bromide are preferred.
Although the amount of the inorganic halide used in the reaction is not
limited, the molar ratio of the halide to the palladium component (A) is
preferably within the range of 10.sup.-2 to 10.sup.3, more preferably
10.sup.-1 to 10.sup.2.
3. Reaction Method and Reaction Condition
Reaction is effected in a reactor in which the aromatic hydroxy compound
and the catalyst comprising the components (A), (B), (C) and (D) or the
components (A), (B) and (E) are charged under heating conditions and
pressures of carbon monoxide and oxygen.
The reaction pre;sure is within the range of 10.sup.-1 to 500 Kg/cm.sup.2,
preferably 1 to 250 Kg/cm.sup.2.
The molar ratio of each of carbon monoxide and oxygen to the hydroxy
compound is within the range of 10.sup.-2 to 50, preferably 10.sup.1 to
10.
Although any desired ratio may be selected as the composition ratio between
carbon monoxide and oxygen, the composition ratio is preferably beyond the
combustion range of these gases from the viewpoint of safety. It is also
effective to dilute these gases with an inert gas having no effect on the
reaction. If the amount of the diluent gas is excessively large, the
partial pressures of carbon monoxide and oxygen are undesirably decreased.
The composition of the reaction gases cannot be determined unconditionally
because the combustion range depends upon the temperature, pressure and
the type of the diluent gas used. Generally, carbon monoxide is used in
excess, and the partial pressures of oxygen is 1 to 10% and dilution gas
used is 0 to 50%, respectively, of the total pressure. When the reaction
gases become short of any one of the gas components due to the reaction
proceeds, the gas component may be supplied under pressure at each time of
shortage, or a gas mixture having a constant composition may be
continuously supplied to the reactor under pressure.
The reaction temperature is 20.degree. to 300.degree. C., preferably
60.degree. to 250.degree. C., and more preferably 80.degree. to
130.degree. C. Although the reaction time depends upon reaction
conditions, the reaction time is generally several minutes to several
hours.
In reaction, an inert solvent such as hexane, heptane, cyclohexane,
benzene, toluene, xylene, methylene chloride, chloroform, chlorobenzene,
diethyl ether, diphenyl ether, tetrahydrofuran, dioxane, ethyl acetate,
methyl formate, acetonitrile can be used. When the aromatic hydroxy
compound as a raw material is used as a reaction solvent, another solvent
need not be used.
After reaction, the high-purity aromatic carbonate produced can be isolated
and purified from the reaction mixture without any other treatment or
after the solid is separated by filtration, by a purification method such
as distillation purification or crystallization. The catalyst components
obtained from the filtration or distillation residue can be recovered and
then used again for the next reaction.
When the catalyst is recovered and used again, it is preferable to use a
catalyst system comprising the components (A), (B) and (E) rather than a
catalyst system comprising the components (A), (B), (C) and (D) because
the former system does not contain a quaternary ammonium salt or
quaternary phosphonium salt (quaternary onium salt) as a component, and
thus exhibits relatively higher thermal stability.
EXAMPLES
The present invention is described in detail below with reference to
examples and comparative examples.
Example 1
3.3 g (35 mmol) of phenol, 26.0 mg (0.012 mmol Pd) of 5%-palladium/carbon,
4.0 mg (0.012 mmol) of cerium (III) acetate monohydrate, 82 mg (0.26 mmol)
of tetra-n-butylammonium bromide and 13 mg (0.12 mmol) of hydroquinone
were charged in a 30-ml Hastelloy autoclave. After air in the system was
replaced by carbon monoxide, 60 Kg/cm.sup.2 of carbon monoxide and 30
Kg/cm.sup.2 of dry air were introduced into the autoclave, followed by
reaction at 100.degree. for 1 hour. As a result of gas chromatoraphic
analysis of the reaction solution, the yield of diphenyl carbonate was 17%
(3.0 mmol).
When reaction was further continued for 2 hours, diphenyl carbonate was
obtained with a yield of 25.8% (4.5 mmol). The yields of phenyl salicylate
and p-phenoxyphenol which were produced as by-products were 0.55% (0.095
mmol) and 0.20% (0.034 mmol), respectively. The selectivity of
p-phenoxyphenol was 0.7%.
Example 2
The same operation as that in Example 1 was performed using 3.1 g (33 mmol)
of phenol, 25.5 mg (0.012 mmol Pd) of 5%-palladium/carbon, 4.0 mg (0.012
mmol) of cerium (III) acetate monohydrate, 101 mg (0.24 mmol) of
tetraphenylphosphonium bromide and 13 mg (0.12 mmol) of hydroquinone.
After reaction for 3 hours, diphenyl carbonate was obtained with a yield
of 23.7% (3.9 mmol). Phenyl salicylate and p-phenoxyphenol were produced
as by-products with yields of 0.55% (0.090 mmol) and 0.15% (0.025 mmol),
respectively. The selectivity of p-phenoxyphenol was 0.6%.
Comparative Example 1
The same operation as that in Example 1 was performed using 3.1 g (33 mmol)
of phenol, 25.6 mg (0.012 mmol Pd) of 5%-palladium/carbon, 4.3 mg (0.012
mmol) of manganese (III) acetylacetonate, 80 mg (0.25 mmol) of
tetra-n-butylammonium bromide and 13 mg (0.12 mmol) of hydroquinone. After
reaction for 1 hour, diphenyl carbonate was obtained with a yield of 10%
(1.6 mmol).
When reaction was further continued for 2 hours, the yield of diphenyl
carbonate was 6.7% (1.1 mmol). The yields of phenyl salicylate and
p-phenoxyphenol, which were by-products, were 0.19% (0.031 mmol) and 0.25%
(0.041 mmol), respectively. The selectivity of p-phenoxyphenol was 3.5%.
Example 3
The same operation as that in Example 1 was performed using 4.5 g (49 mmol)
of phenol, 12.7 mg (0.006 mmol Pd) of 5%-palladium/carbon, 2.0 mg (0.006
mmol) of cerium (III) acetate monohydrate, 127 mg (0.40 mmol) of
tetra-n-butylammonium bromide and 21 mg (0.19 mmol) of hydroquinone. After
reaction for 3 hours, diphenyl carbonate was obtained with a yield of
12.6% (3.0 mmol). Phenyl salicylate and p-phenoxyphenol were produced as
by-products with yields of 0.30% (0.073 mmol) and 0.18% (0.044 mmol),
respectively. The selectivity of p-phenoxyphenol was 1.4%.
Comparative Example 2
The same operation as that in Example 3 was performed using 4.5 g (48 mmol)
of phenol, 3.0 mg (0.006 mmol Pd) of 5%-palladium/carbon, 2.1 mg (0.006
mmol) of cerium (III) acetate monohydrate and 121 mg (0.38 mmol) of
tetra-n-butylammonium bromide. After reaction for 3 hours, diphenyl
carbonate was obtained with a yield of 7.4% (1.8 mmol). Phenyl salicylate
and p-henoxyphenol were produced as by-products with yields of 0.21% (0.05
mmol) and 0.38% (0.09 mmol), respectively. The selectivity of
p-phenoxyphenol was 4.7%.
Example 4
3.0 g (32 mmol) of phenol, 25.8 mg (0.012 mmol Pd) of 5%-palladium/carbon,
4.2 mg (0.012 mmol) of cerium (III) acetate monohydrate, and 5.18 mg (0.24
mmol) of cesium bromide were charged in a 30-ml Hastelloy autoclave. After
air in the system was replaced by carbon monoxide, 60 Kg/cm.sup.2 of
carbon monoxide and 30 Kg/cm.sup.2 of dry air were introduced into the
autoclave, followed by reaction at 100.degree. C. for 3 hours. As a result
of gas chromatographic analysis of the reaction solution, the yield of
diphenyl carbonate was 9.4% (1.5 mmol). The yields of phenyl salicylate
and p-phenoxyphenol which were produced as by-products were 0.32% (0.05
mmol) and 0.13% (0.02 mmol), respectively. After the completion of
reaction, the gas phase contained 0.4% of carbon dioxide.
Examples 5 to 9
The same reaction as that in Example 4 was effected except that each of the
various halides were used in place of cesium bromide. The halides used,
the amounts thereof and the yields of diphenyl carbonate are shown in
Table 1.
TABLE 1
______________________________________
Yield of diphenyl
Example No. Halide (mg) carbonate (%)
______________________________________
5 CsCl (41) 8.4
6 NaBr (26) 5.0
7 KBr (29) 5.6
8 RbBr (40) 8.7
9 BaBr.sub.2.2H.sub.2 O
(81) 4.1
______________________________________
Comparative Example 3
The same operation as that in Example 4 was performed using 3.0 g (32 mmol)
of phenol, 25.6 mg (0.012 mmol Pd) of 5%-palladium/carbon, 3.0 mg (0.012
mmol) of cobalt (II) acetate tetrahydrate, and 51.4 mg (0.24 mmol) of
cesium bromide. As a result, diphenyl carbonate was obtained with a yield
of 1.5% (0.24 mmol). After the completion of reaction, the gas phase
contained 0.3% of carbon dioxide.
Comparative Example 4
The same operation as that in Example 4 was performed using 3.0 g (32 mmol)
of phenol, 25.8 mg (0.012 mmol Pd) of 5%-palladium/carbon, 4.2 mg (0.012
mmol) of cerium (III) acetate monohydrate, and 62.7 mg (0.24 mmol) of
cesium iodide. As a result, diphenyl carbonate was obtained with a yield
of 0.8% (0.12 mol). After the completion of reaction, the gas phase
contained 10.6% of carbon dioxide.
Example 10
12.0 g (128 mmol) of phenol, 101 mg (0.048 mmol Pd) of 5%-palladium/carbon,
16 mg (0.048 mmol) of cerium (III) acetate monohydrate, and 165 mg (0.98
mmol) of cesium chloride were charged in a 50-ml astelloy autoclave. After
air in the system was replaced by carbon monoxide, 60 Kg/cm.sup.2 of
carbon monoxide and 30 Kg/cm.sup.2 of dry air were introduced into the
autoclave, followed by reaction at 100.degree. for 3 hours. As a result,
the yield of diphenyl carbonate was 7.3% (4.7 mmol). After the reaction
solution was transferred to a 50-ml flask, the solution was heated to
50.degree. C. under reduced pressure to distill off phenol, and was
further heated to 150.degree. C. to distill off diphenyl carbonate. The
residual catalyst was put in an autoclave, and 11.4 g (121 mmol) of phenol
was added thereto. After air in the system was replaced by carbon
monoxide, 60 Kg/cm.sup.2 of carbon monoxide and 30 Kg/cm.sup.2 of dry air
was introduced into the autoclave, followed by reaction at 100.degree. C.
for 3 hours. As a result, diphenyl carbonate was obtained with a yield of
6.8% (4.1 mmol).
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